TM 5-3805-280-24-1
Thread coupling/uncoupling adjustments
THREAD COUPLING/UNCOUPLING ADJUSTMENTS
The drifter displacement, during thread coupling/
Rest the hand holding the screwdriver on the
uncoupling operations, must be synchronized with
guide.
the rotation speed in accordance with the thread
Place the screwdriver in the thread.
pitch.
Ask a helper to operate the rod changer manipula-
The drifter rotation/displacement synchronization
tor lever in thread coupling position.
is obtained by controlling the drifter speed by means
of 2 flow limiters located on the drilling automatism
The synchronization is correct if the screwdriver
block.
remains in position (the drifter displacement corre-
sponds exactly to the thread pitch).
If the screwdriver tends to move up or down, ad-
just the drifter displacement by setting the flow regu-
lator F:
The drifter displacement is too fast, loosen
the setting F.
The drifter displacement is too slow, tighten
the setting F.
Thread uncoupling synchronization
The checking procedure is the same, but, operate
R
the rod changer lever in thread uncoupling position
and set the flow regulator R :
F
Tighten the setting R if the drifter displace-
ment is too fast,
Loosen the setting R if the drifter displace-
ment is too slow.
The flow regulator F controls the drifter forward
speed.
The flow regulator R controls the drifter reverse
speed.
Thread coupling synchronization
The verification of the synchronized drifter dis-
placement/rotation is done by checking the displace-
ment of a screwdriver placed in the shank thread.
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